Re: CCL:DFT & metal metal bonds

[jmmckel %! at !% attglobal.net]

 I recall using the relativistic ECP's in deMon [also in DGAUSS] for the
 Ag dimer.
 The 17 valence ECP was better than the 11 or 1 electron ECP's, and was
 better than
 all the all electron non-relativistic results.
 John McKelvey
 Marcel Swart wrote:
 > >You want to elaborate on this? Is it because of the STOs? As to GTO's I
 > >use TZVP/P basis sets, which are not too bad usually.
 >
 > Yes, the STO's are always much better. But not only that. It is a
 > very clever program, making the calculations very efficient when
 > looking at CPU-time, parallellization, those kind of things.
 >
 > >  > Furthermore, did you also include relativistic effects ?
 > >
 > >yes, scalar relativistic via the ECP.
 >
 > Well, that's not really what I meant. You assume that the ECP's mimic
 > the relativistic effects you are after, but it is not the same as
 > including the relativistic effects themselves !!!
 >
 > >  > I guess when you look at Tungsten/Molybdenum, these can be quite
 > >significant.
 > >>  Again this is a YES to ADF, since in this program these effects
 are
 > >  > easily taken into account.
 >
 > Also, I know from work from my Professor (yet unpublished I think),
 > who is an expert in Relativistic Quantum Chemistry (J.G. Snijders),
 > that these relativistic effects are needed for heavy atom dimers. If
 > you don't include them (properly), the calculations are not
 > performing very well.
 >
 > Marcel.
 >
 > -= This is automatically added to each message by mailing script =-
 > CHEMISTRY %! at !% ccl.net -- To Everybody    |   CHEMISTRY-REQUEST %! at
 !% ccl.net -- To Admins
 > MAILSERV %! at !% ccl.net -- HELP CHEMISTRY or HELP SEARCH
 > CHEMISTRY-SEARCH %! at !% ccl.net -- archive search    |    Gopher:
 gopher.ccl.net 70
 > Ftp: ftp.ccl.net  |  WWW: http://www.ccl.net/chemistry/   | Jan: jkl %! at !% ccl.net